Suppressive Effects of Copper Sulfate Accumulation on the Spermatogenesis of Rats.

This study investigated the effect of copper sulfate (CuSO4) in the rat spermatogenesis. Forty male rats, weighing 70-80 g, were randomly divided into four groups: control group (CG, 0 mg/kg BW), low-dose group (LG, 100 mg/kg BW), mid-dose group (MG, 200 mg/kg BW), and high-dose group (HG, 400 mg/kg BW). Rats were administered CuSO4 by gavage for 30 days. A variety of measurements were taken including the testis coefficients, the sperm count, the abnormal malformation rate, testosterone (T), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) concentrations in the serum. In addition, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities, and malondialdehyde (MDA) concentration in the testis were determined. The results showed that in the CuSO4-treated groups, the testis coefficients, sperm count, T, LH, and FSH concentrations, and GSH-Px and SOD activities decreased, while the abnormal malformation rate and MDA concentration increased, compared with the CG. It indicates that CuSO4 exposure impairs the sperm quality and inhibits secretion of sex hormone and gonadotropin, and testis anti-oxidative function, suppressing the rat spermatogenesis.

Mechanism of BMP and TG2 in mesenchymal stem cell osteogenesis.

OBJECTIVE: To study the interactive effects of Type II glutamine transaminase (TG2) and bone morphogenetic protein-9 (BMP-9) in the induction of osteogenesis in mice mesenchymal stem cells (MSCs) C3H10T1/2 model. MATERIALS AND METHODS: Batches of MSCs C3H10T1/2, divided into two groups, were treated with BMP-9 (control group) or BMP-9 and TG2 (experimental group) under oxygen deficient conditions. The secreted alkaline phosphatase (SEAP) chemiluminescence and the histochemical staining methods were used to detect the alkaline phosphatase (ALP) expression. The alizarin red S staining was used to detect the calcium salt precipitation and the caspase-3 protein expression was monitored using Western blot. Flow cytometry was employed to identify cell cycle, and trypan blue exclusion method to count the living cells and monitor cell proliferation. RESULTS: The levels of ALP expression in the experimental group were much higher than that of the control group. The level of expression of advanced caspase-3 protein was significantly lower (p < 0.05) in the experimental group than in the control group. The highest fraction of cells in the experimental group was in the phase M while cells in the control group were in the interphase. Moreover, cell number in the experimental group was significantly increased (p < 0.05) relatively to the control group. CONCLUSIONS: BMP-9 interacts with TG2 in osteogenesis of MSCs C3H10T1/2 cells. Further studies are needed to understand the exact mechanism of BMP9/PG2 interactions in osteogenesis.

Effects of 5-HT3 receptor antagonism on hippocampal theta rhythm, memory, and LTP induction in the freely moving rat.

Serotonergic brainstem projections to hippocampus are thought to preferentially target and increase, via 5-HT3 receptors, the excitability of a distinct subpopulation of interneurons that primarily regulate GABAB-mediated inhibition in the dendritic region of pyramidal cells. Hippocampal slice work suggests that the between-burst hyperpolarization caused by slow (GABAB) IPSPs plays a significant role in controlling the strength of LTP induced with theta burst stimulation. According to the above observations it was assumed that blockade of hippocampal 5-HT3 receptors should reduce the hyperpolarization and thereby enhance both the frequency of the naturally occurring theta rhythm and the induction of LTP; moreover, if LTP-like mechanisms provide the substrate for certain forms of memory, such treatment was expected to facilitate learning. Each of the above predictions was tested and confirmed in the present set of experiments. The effects of ondansetron, a potent and selective antagonist of the 5-HT3 receptor, were examined on (1) frequency of the hippocampal theta rhythm, (2) induction of LTP in field CA1 of freely moving rats, and (3) retention of olfactory and spatial memory in tasks known to depend on an intact hippocampus. When injected intraperitoneally into freely moving rats, the drug reliably and significantly increased the frequency of the hippocampal theta rhythm in a dose-dependent manner. Second, at concentrations that facilitate theta frequency (100 micrograms/kg and 500 micrograms/kg), an injection of the drug 30 min prior to delivering electrical stimulation bursts significantly increased the magnitude and duration of LTP compared to that obtained in the same animals after vehicle injections.(ABSTRACT TRUNCATED AT 250 WORDS)

Centrally active modulators of glutamate receptors facilitate the induction of long-term potentiation in vivo.

An experimental drug, 1-(1,3-benzodioxol-5-ylcarbonyl)piperidine, that facilitates glutamatergic transmission in brain after systemic administration was tested for its effects on the induction of long-term potentiation in the hippocampus of rats. Intraperitoneal injections of the drug markedly increased the degree and duration of long-term potentiation; similar results were obtained with an analogue of 1-(1,3-benzodioxol-5-ylcarbonyl)piperidine that was also found to improve retention of memory in a radial maze task and in an odor-matching problem. These results define tools for enhancing long-term potentiation in vivo and confirm an important prediction from the hypothesis that long-term potentiation is a substrate of memory.

[Effect of 2-naphthyl-3- (3,4-dimethoxy) phenyl-propenoic acid on the metabolism of arachidonic acid in rabbit platelets].

Washed rabbit platelets were incubated with [14C] arachidonic acid (AA sodium salt) after being exposed to 2-naphthyl-3-(3,4-dimethoxy) phenyl-propenoic acid (NM-PA), indomethacin (Ind) and imidazole (Imi) or control solvent. The metabolites of AA in rabbit platelets were separated with the system of chloroform: methanol: acetic acid: water (90:8:1:0.8) by thin layer chromatography and quantitated by liquid scintillation counter. The metabolism of AA was influenced by NMPA dose-dependently in the range of 0.05-0.5 mmol/L. The formation of thromboxane B2 (TXB2) and 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT), the final metabolites in the pathway of cyclooxygenase-thromboxane synthetase, were decreased from 24 +/- 6.7 to 3.2 +/- 1.6% and 10.3 +/- 2.49 to 4.7 +/- 2.8%, respectively. Meanwhile, 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE), the metabolite in the pathway of lipoxygenase, was increased from 11.9 +/- 1.7 to 34 +/- 5.6%. It is suggested that NMPA blocks the pathway of cyclooxygenase-thromboxane synthetase and then changes the direction of arachidonate metabolism in platelets, the activation of platelets is inhibited in this way.